Exhaust Brakes add power to diesel engines when they're not braking because the increasing diameter of the housing and turbine outlet pipe reduces exhaust backpressure, the company says. So Banks took the idea a step further. If you don't want the exhaust brake, you can boost power and fuel economy with the Power Elbow. Banks says the Power Elbow for '99 through '02 Ford Powerstrokes, with a 3.5-inch outlet, moves 40 percent more air than the stock components. The Elbow for '98 through '02 Dodge 24-valve diesels, with a 4-inch outlet, flows 60 percent better than stock.